Fluorescently-tagged aminoglycosides have been synthesized by randomly coupling amine-reactive fluorescent dyes to amino groups of these antibiotics [Hamasaki & Rando, 1998; Tok, Cho, & Rando, 1999]. However, they are unsatisfactory for use in high-throughput screens because 1) amino groups critical for high affinity binding of the ribosomal RNA A-site have been modified and 2) the ribosomal RNA A-site binding does not change their fluorescence intensity and binding constants can only be extracted by monitoring changes in fluorescence anisotropy.
It is desirable to have nucleic acid probes which bind all type of nucleic acid, such as double stranded DNA, RNA, four stranded DNA/RNA or major groove interactors. The disclosed compositions and methods provide solutions to these problems in the art. The disclosed compositions and methods provide nucleic acid probes that will bind all forms of nucleic acid, and which will bind in such a way that the functional groups involved in DNA interactions are not used to attach the fluorescent tags.